Apparatus for forming composite curved printing plates



A. LENGEL 2,291,188

APPARATUS FOR FORMING COMPOSITE CURVED PRINTING PLATES July 28, 1942.

Filed Feb. '7, 1941 2 Sheets-Sheet 1 INVENTOR. Ines/er z. LEA/GEL ATTOHNCX ayw%.

July 28, 1942. A. L. LENGEL 2,291,188

APPARATUS FOR FORMING COMPOSITE CURVED PRINTING PLATES Filed Feb. 7,1941 2 Sheets-Sheet 2 INVENTOR. 4485m- L. Len/ea 94 1/2 A r TORNEY.

Patented July 28, 1942 U-iTED- STATE :TENT OFFICE APPARATUS FOR FORMINGCOMPOSITE CUR-VED PRINTING PLATES 15 Claims.

This invention relates to 1 cylindrically curved sheet metal printingplatesof thetype which are secured to a similarly curved rigid shelltoform a composite unit adapted formounting directly on the type cylinderof a'rotary printing press in place of the usual curved-stereotypeplates as used in newspaper printing, so that the printing may be donefrom the original engraved or'rather etched plates instead of fromstereotypes 'or electrotypes made therefrom.

The'principal object of the'invention is to provide an improvedcylindrically curved composite plate of the 'kindabove set out andapparatus for producing'it.

Other'ieatures and advantages. of the improvement will appear in thefollowing description and accompanying drawings:

In the drawings:

Fig. 1 is a perspective view'of one of the improved cylindrically curvedcomposite printing plates as produced by my apparatus.

Fig. 2 is a plan View of the apparatus with its dies in closed positionasseen before folding the margins of the thin printing plate over theedges of the rigid supporting-shell.

Fig. 3 isa longitudinal cross section of the apparatus of Fig. 2 as seenfrom the line 3-3 thereof.

Fig. 4 is an enlarged cross section of Fig. 2 taken along the line 44thereof.

Fig. 5 is an enlarged fragmentary section of the base or concave diemember showing the construction of the disappearing centering pins.

Fig. 6 is an enlarged fragmentary section showing the means of securingthe margins of the thin printing plate to the edges of itsrigid'supporting shell.

Fig. 7 is a view similar to that of Fig. 6 but showing a modification inthe manner of securing the thin printing plate to its rigid supportingshell.

Fig. 8 is an enlarged detail of one of the cornets of the rigidsupporting shell showing the thin printing plate extending thereover.

'Fig. 9 is an enlarged'perspectiv'e view of one of the link guidingblocks.

Figs. 10 and 11 are respectively front and side views of the hook forclamping the dies closed;

Fig. 12 is a plan view of the'handwheel' stop.

Fig. 13 is a fragmentary section taken along the line I 3-4 3 of Fig. 2.

Before describing the invention it may be said that it is not new tosecure a thin flexible printing plate around a rigid press cylinder, orfirst to a rigid curved plate for thereafteriattaching the latterto thecylinder of a printingpress, the same having been used principally onlithographic presses for years, and more recently some work' has beendone in, connection with the similar mounting of half tonean'd'similartypographic plates, but which by reason of their thickness and lack offlexibility have required rolling or forcible bendingto the proper curvebefore attaching to the press cylinder or intermediate support. Myimprovement is to eliminate several of the difiiculties involved whichhave heretofore prevented the wide-use of such curved original plates onrotary typographic presses.

In the practice of my invention'wit-h a so-called half tone reliefplate, or its equivalent in having an ink roller supporting rdotstructure on its printing surface, the plate is etched on a very thinflexible sheet of'metal such as a zincsheet about .032 of an inch thick,and whichsheet will readily assume the curve of the printing cylinder orintermediate curved supporting shell without any forcible bendingoperation, as it will conform thereto by merely wrapping it about thecylinder. However, instead of proceeding in this customary manner andmeeting the' difficulties of accurately locating the: plate and maintaining the desired register, especially as is required for color workwhere several successive plates are used, I provide a curved press orclamping device which may be termed a pair of die members though theyare not actually used for pressure formingbut only to'hold the plate andits shell in close contact and accurate register during the assemblingand securing together of the composite printing plate member.

The base'member'of these dies is formed with a substantiallyhalf-cylinder concavity with its open side up, and the other die is aconVexly curved counterpart hingedly' connected to the base member so asto swing into or out of it, in predetermined exact relation, but "whenin the nesting position thereis a free space between the 'diesurfacesexactly equal to the combined thickness of the thin flexible printingplate and the thickness of a sheet of paper of definite thickness orweight, plus the thickness of the rigid curved supporting shell, thelatter being about .410 in thickness, or so that the combined thicknessof theshell with its plate will be'the same as the curved stereotypeplates for the particular printing press for which the compositep'lateis wanted.

The base die member is provided with plate locating meanswithin it whichaccurately position the thin printing plate when the latter is merelypushed or rather sprung into it by hand with its printing side facingthe die (a sheet of paper having first been inserted in the die cavityto protect it). The rigid supporting half-cylindrical shell has in themeantime been attached to the convex surface of the other die memberwhile swung to open position for accessibility, and the die members arethen closed to swing the convex side of the rigid shell snugly withinthe concave side of the sheet metal printing plate, and the die membersare tightly latched together. No great force is required on the diemembers as the weight of the upper or convex member and its tighteninglatch is suflicient to insure perfect contact of the thin plate with itsconvex supporting shell.

When in such position in the dies the thin printing sheet extends atboth of its straight ends beyond the straight ends of the supportingshell and means is provided for simultaneously folding these extendingends directly across the ends of the supporting shell and securing themthereto, and after which the upper die member is swung out on its hingesand brings with it the completed composite printing unit, i. e. therigid supporting shell with the thin flexible printing sheet firmlysecured to it in predetermined registered position, and which unit isthen released from the outer die to which it was clamped and is readyfor similar clamping to the printing press cylinder in the same way as astandard curved stereotype plate.

In the drawings Fig. 1 shows the completed unit consisting of the rigidhalf-cylindrical shell I which is preferably made of steel of an overallsize and with its curved ends beveled off at 2 exactly the same as astandard curved stereotype plate to fit in the clamps of a rotaryprinting press. On the convex side of the rigid shell is the'thinflexible printing plate 3 held smoothly and tightly therearound byscrews or special fastening means 4 passing through the inwardly foldedstraight end margins 5 of the sheet. The corners of the rigid shell arerounded at 6 where the sheet is bent over them for two reasons; first,to prevent cracking the sheet, and second to cause the ink roller of thepress to ride up somewhat gradually to the printing surface instead ofstriking an abrupt corner, for attention is called to the fact that inthe preferred form of my composite printing unit as applied totypographic printing there is a printing dot structure such as on halftone printing plates, which is coextensive with the entire surface ofthe plate on its rigid support and that the dot structure extends notonly over all etched areas large enough to require them as an ink rollersupport to prevent inking the bottom of the necessarily shallow etchedportions of so thin a plate, but the smallest or minimum printing pointdot structure extends over the margins and the curved corners 6 as welland as shown at I in the greatly magnified view of Fig. 8. This is animportant feature which permits the use of such a, thin flexibletypographic printing plate, and without it the plate would have to bethe thicker stifi metal plates as generally used for half tone blocks,as forcible bending to form, and also routing of all large blank areaswould be required, and which latter is not possible on the thin flexibleplates used in my unit. My composite curved printing plate unittherefore differs basically from any prior curved printing plate withwhich I am familiar.

Figs. 2, 3 and 4 show the main features of construction of the unitassembling apparatus and in which 8 is the base or lower die memberformed with the substantially half-cylinder concavity 9 and with theoutwardly extending shelves l0 along its upper edges, upon which thelongitudinally extending folding bars II are slidably positioned.

The base member 8 is preferably a rigid iron or steel casting accuratelymachined on its surfaces 9 and I0, ribbed as at l2 and provided with afoot flange l3 having holes M for holding down bolts.

The thin printing plate cut accurately to rectangular size is shown at 3sprung within the concavity 9 of the die member and with its printingface against a sheet of paper l5 and accurately sidewise located by thefour marginal pins 16 resiliently urged upward by springs 11, andendwise located by overhanging lips 18 which project inwardly from theconfronting edges of the margin folding bars I l a distance about equalto the thickness of the printing plate 3 and under which lips theaccurately cut plate is pushed when it is placed into the concavity ofthe die.

The margin folding bars H are slidably held down upon the shelves III byoverhanging guide plates l9 at opposite ends and a similar plate 20 atan intermediate point.

The upper or convex part of the die is a rigid substantiallyhalf-cylindrical casting 2| reinforced with deep ribs 22 finished on itsface to exactly the same diameter as the rotary printing press cylinderfor which the printing plates are intended and it is provided along onearched edge with a fixed overhanging lip 23 beveled to match the beveledportion 2 of the rigid supporting shell I and provided with a couple ofsimilarly beveled clamps 24 which engage over the bevel at the oppositeedge of the shell and which may be moved inward to clamp the shell, oroutward to release it by turning the handwheels 25 or screws 26 whichare threaded through the vertical wall 21 of the die member and upon theenlarged bare shanks of which screws the clamps are slidable, andfurther similarly guided on pins 28 to prevent the clamps from turning.

This upper die member 2| is formed or provided with a later'allyextending hinge bracket 29 which is hingedly connected by a pin 30 witha similar bracket 3| secured to or formed on the lower die member sothat the upper one may be swung into and out of the lower one by meansof the Handle 32, and when in the lower or closed position it may belocked as by means of a latch 33 which is pivoted at 34 to the basemember and engages over the shank 32 of the handle. The latch is pivotedto an eccentric pin 63 provided with vise handle 64 for tightening afterhooking.

The top side" of the upper die member 2| is generally open and across itis a heavy cross shaped plate 35 preferably cast integral therewith andsupported on ribs, and which plate, together with marginal ribs 22'holds the curved wall 2| rigid. Pivotally mounted on plate 35 are fourlink guiding blocks 31 which slidably receive and guide four flat links39 provided at their outer ends with firmly secured studs 40 projectingdownwardly respectively into holes drilled into bars ll. (See Fig. 4.)Blocks 31 are centrally pivoted to the plate 35 as by suitable screws orrivets 38. (See Fig. 9.)

At their inner ends links 39 are pivotally connected at H and 42 to flatgear sectors 43 in turn pivoted at 44 to the plate 35. The teeth 45 ofthe gear sectors are in spaced confronting .38 1are quite tightfittingiagainst ithe topof the links 39 so'ith'at thel'frictioniset iupwillkhold :relation and in mesh with soppositesideszof: aispur pinion-46which is: securedito a verticalshaft'fl pivotally extendinglthroughplate 351an'd3afhub 36 formed thereon and heldv from withdrawal by acollar. A handwhel49xissecure'd to'the upper end of the shaft 41 and thepositioniof the gear segments is so arranged so that a twist of the.handwheel in one direction will pull both folding'bars inward and viceversa. To limit the maximum movement of the foldingibarsll in or out, ahandwheel stop arm 50 secured to shaft 41 is provided with adjustablestop screws-'50 which alternately come'against a stop pin 60 projectingfrom plate35.

Along both inner margins of the foldingbars I I is .a row of'drilledholes 5I, which, when the bars are pulled to theirinnermostposition, will be exactly aligned over a similar row of holes 52 drilledin thefiat .upperedges of the rigid shell, 3. (See Figs'6 and 7.)

In operating the apparatus, whenthe upper die member is swung open, itis lowered to the dotted line 58 in Fig. -3 to rest its thin lower edgesupon across support 59 and'against'which the two straight edges ofthe'rigid shell I will also rest when slipped on the convex surfac'eofthe die and clamped in place, as all supporting shells used with .thedie will be accurately machined to exactly th'e same size and will bebrought into flush relation with the die at the edges by this means andthus insure a'predetermined'position with regard to the thin printingplate'registered in the base die, when the dies are closed. When the twofolding bars'II aresimultaneously pulled inwardly from dotted position II shown in Figs. '6 and? by means of the handwheel, they push ahead ofthem the straight marginal portions of the printing plate whichlproiectabove the upper edges of the rigid shell I to themwardly extending stoplips I8 and hold these margins at right angles'snugly over the edges ofthe rigid shell to the position shown in Fig. 6. 'In thus holding themargins of the thin printing plate there is a drawing action whichtakesall slack out of the plate and stretches 'it tightly about the convexsurface of the 'rigid shell.

After the margins have been folded over, two ways are illustrated forsecuring the folded margins to the shell. In Fig. 6 the holes 52 areshown tapped "and also countersunk as 'at 53, and when a pointed punchof the character shown at 54 is driven through'the aligned holes 5I and52 it will break through the printing plate and spread its ragged margininto the countersunk portion of the holes, so that after all are punchedthe bars II 'may'be backed off sufficiently to permit screws 4 to beinserted to hold the folded margins in place. The ragged margins forcedinto the countersunk portion of the holes will effectively prevent any:displacement of the margins before the screws are in place.

A variation of the fastening means is shown in Fig. 7 wherein the holes52 in the rigid shell are of a size and under cut close to their endsasat 55 so that when the punch 54 is driven through the printing plate theragged margins will be forced outwardly into the undercut portions asindicated at 56 to lock thereunder and thereby dispense with any othersecuring means, and the thin printing plate together with its rigidsupporting shell may be taken from the opened dies as a unit ready forplacing on the press cylinder.

In considering the operation of-the die mem bers, it should benoted-that the guide members folding bars outwardly so' that the innerdie member'with its completed acomposite plate can be swung upwardly outof thelower die, the outward movement'of the folding bars is sufiicientto carry'the lips I8 far enough to clear .the upper corner of theprinting'plate 3 attached to its curved 'shell I, and this will beassured by turning the wheel as far as permitted by stop pin 60.However, as these lips I8 must overhang and form stops for the upperedges of the curved printing sheet or plate 3 when it is placed in theconcave die, means is provided for bringing these folding bars to properposition before putting the sheet in the lower die. This means is shownin Fig. 13 and consists of-a stop block 6| drilled to fit over fixedstop pins 62 to bring the outer edge 65 of the block in position to stoplip I8 when in correct position. To use the block 6|, the upper diemember is first temporarily lowered, stop block BI is put in position(as indicated by dotted lines in Fig 2) the handwheel is'turnedsufliciently to pull the folding bars inwardly until one of them strikesthe strip block, the stop block is then removed, and the upper die swungout again. The bars II are now in position shown in full lines in Fig.13, (and as shown dotted in Figs. 6 and '7) ready to receive the sheetand the shell for attaching the'two as described. Block BI is providedwith a lifting knob 66.

It should be noted that while I have described the dies and the rigidsupporting shell generally as half cylinders, they are in fact somewhatless than a half cylinder to make room for the substantially one inchwide stops usually provided on the-printing press cylinder which comebetween the junctures of each pair of shells secured around thecylinder, as is the case with the regular curved stereotype plates,though for special presses the actual degrees of a circle included inthe cylindrical segments may be made to suit. Also the combinedthickness of the printing plate and its supporting shell is generallyabout but this also willlvary for some presses, and any composite platewill always be made to meet the stereotype thickness required for theparticular press upon which it is to be used.

The words half-cylindrical or semi-cylindrical used herein and in theclaims are intended to include any variation in length of arc of themembers as required for various printing presses for which the inventionis applicable.

Having thus described my invention, itsmode of operation and wherein itis an improvement over the prior art insofar as the same is known to me,what I claim is:

1. Apparatus for forming cylindrically curved printing plates comprisinga convexly curved block substantially 0f half-cylindrical form, meansadapted for securing-a correspondingly curved cylindrical shell segmentupon the' face of said block, a concave cylindrically curved base intowhich said block and its shell segment are adapted to be received, meansfor definitely locating a thin arched printing plate within theconcavity of said base, means supporting said block for movement withits shell segment into the concavity of said base to rest upon thearched printing plate therein, and with the straight ends of said plateextending beyond the straight ends of said shell, and means for bendingthe extending ends of said plate across said ends of the shell.

2. Apparatus for forming cylindrically curved printing plates comprisinga convexly curved block substantially of half-cylindrical form meansadapted for securing a correspondingly curved cylindrical shell segmentupon the face of said block, a concave cylindrically curved base intowhich said block and its shell segment are adapted to be received, meansfor definitely locating a thin arched printing plate within theconcavity of said base, means pivotally supporting said block forswinging with its shell segment into the concavity of said base to restupon the arched printing plate therein, and with the straight ends ofsaid plate extending beyond the straight ends of said shell, and meansfor bending the extending ends of said Plate across said ends of theshell.

3. Apparatus for forming cylindrically curved printing plates comprisinga convexly curved block substantially of half-cylindrical form, meansadapted for securing a correspondingly curved cylindrical shell segmentupon the face of said block, a concave cylindrically curved base intowhich said block and its shell segment are adapted to be received, meansfor definitely locating a thin arched printing plate simultaneously fromits four edges within the concavity of said base, means supporting saidblock ior movement with its shell segment into the concavity of saidbase to rest upon the arched printing plate therein,. and with thestraight ends of said plate extending beyond the straight ends of saidshell, and means for bending the extending ends of said plate acrosssaid ends of the shell.

4. In a structure as set out in claim 1, the printing plate locatingmeans within the concavity of said base including pins projecting out ofthe concave surface of said base adapted to engage the opposite edges ofthe plate, and means mounting the pins for resilient protrusion from thebase, whereby they may be depressed into the base when the block is inposition.

5. In a structure as set out in claim 1, the printing plate locatingmeans within the concavity of said base including pins projecting out ofthe concave surface of said base adapted to engage the opposite edges ofthe plate, and means mounting the pins for resilient protrusion from thebase, whereby they may be depressed into the base when the block is inposition, and overhanging lips at the two straight edges of theconcavity of the base against which lips the straight edges of thearched printing plate abut when in position within the concavity.

6. In a structure as set out in claim 1, the printing plate locatingmeans within the 'concavity of said base including pins projecting outof the concave surface of said base adapted to engage the opposite edgesof the plate, and means mounting the pins for resilient protrusion fromthe base, whereby they may be depressed into the base when the block isin position, and

(ill

overhanging lips at the two straight edges of the concavity of the baseagainst which lips the straight edges of the arched printing plate abutwhen in position within the concavity, two longitudinally extending barsrespectively at the opposite straight edges of the concavity of the baseand upon which bars said lips are formed, and means mounting said barsfor sliding toward one another for bending the extending edges of theplate across the straight ends of the cylindrical shell segment.

7. Apparatus for forming cylindrically curved printing plates comprisinga substantially halicylinder concave die member and a convexsubstantially half-cylinder die member adapted to clamp between them arigid curved half-cylindrical shell within the concavity of a curvedthin printing plate positioned in said concave die member, the concavedie member provided with a shelf extending outwardly at oppositelongitudinal edges, a .pair of bars respectively on said shelves, meansguiding said bars for bodily sliding on said shelves toward and from oneanother for folding any extending ends of said printing plate inwardacross the longitudinal rear edges of the half-cylindrical shell, and arow of openings extending through said bars in position to align over arow of holes formed in the rear edges of said shell when the bars areslid inward toward one another, and stop means limiting inward movementof the bars when the holes and openings are so aligned.

8. Apparatus for forming cylindrically curved printing plates comprisinga substantially halfcylinder concave die member and a convexsubstantially half-cylinder die member adapted to clamp between them arigid curved half-cylindrical shell within the concavity of a curvedthin printing plate positioned in said concave die member, the concavedie member provided with a shelf extending outwardly at oppositelongitudinal edges, a pair of bars respectively on said shelves, meansguiding said bars for bodily sliding on said shelves toward and from oneanother for folding any extending ends of said printing plate inwardacross the longitudinal rear edges of the half-cylindrical shell, andmeans comprising a hand-wheel, means rotatably mounting said handwheelon the rear of said convex die member, and links and levers operativelyconnecting said handwheel to and for operating both sliding barssimultaneously.

9. Apparatus for forming cylindrically curved printing plates comprisinga substantially halfcylinder concave die member and a convexsubstantially half-cylinder die member adapted to clamp :between them arigid curved half-cylindrical shell within the concavity of a curvedthin printing plate positioned in said concave die member, the concavedie member .provided with a shelf extending outwardly at oppositelongitudinal edges, a pair of bars respectively on said shelves, meansguiding said bars for bodily sliding on said shelves toward and from oneanother for folding any extending ends of said printing plate inwardacross the longitudinal edges of the half-cylindrical shell, and meanscomprising a handwheel rotatably mounted on the back of the convex diemember, a pinion rotatable with said handwheel, a pair of pivoted gearsegments engaged by said .pinion, and links connected to said gearsegments provided with pivotal connections to said bars for operatingboth sliding bars simultaneously.

10. In the construction set out in claim 9,

means frictionally retaining said links in positions of movement, andthe pivotal connections of said links to said bars including pinsprojecting from one of the connecting members adapted to enter holesformed in the other of the connecting members.

11. In the construction set out in claim 9, means \frictionallyretaining said links in positions of movement, and the pivotalconnections of said links to said bars including pins projecting fromone of the connecting members adapted to enter holes formed in the otherof the connecting members, said bars formed with a row of holes broughtinto alignment with a similar row of holes in the extreme outer edgesrespectively of said half-cylindrical shell when the bars are movedtoward one another to a predetermined limit, and stop means prescribingsuch limit of movement.

12. In a structure as set out in claim 2, a handle projecting from saidblock at a :point remote from its pivotal support, and means forlatching the block to said base when swung into position therein.

13. In a structure as set out in claim 2, means for definitely locatingsaid shell segment upon said convexly curved block when securing itthereto.

14. In a structure as set out in claim 1 said block being asemi-cylindrical shell, a plate extending across the concave side of theshell and tying the ends of its walls against deformation, and meansoperatively mounted on said .plate for manually operating said means forbending the extending ends of said plate.

15. Apparatus for forming cylindrically curved printing platescomprising a substantially halfcylindrical concave die member into thecurved concavity of which a thin flexible printing plate is adapted tobe fitted with its straight ends projecting out of the concavity of thedie, a substantially half-cylindrical convex die member, means forclamping upon said convex die member a curved substantiallyhalf-cylindrical shell, said shell being of a size and curve to fitwithin the concavity of said flexible printing plate when positioned inthe concave die member, and means for clamping the die members togetherwith the shell and plate between them, a pair of flat bars extendingrespectively along opposite straight edges of the dies when clampedtogether, means mounting said bars for movement to fold the projectingends of said printing plate inward across the rear edges of said shell,said bars provided with a row of openings adapted to align over a row ofholes formed in the rear edges of said shell, and stop means limitingthe inward movement of said bars when the openings and holes are soaligned.

ALBERT L. LENGEL.

